Buggy code:
public class Compiler { final int option ; class CodeBlock { Instruction head ; int start ; int end ; } public UList < Instruction > codeList ; UMap < Compiler . CodeBlock > ruleMap ; HashMap < Integer , MemoPoint > memoMap ; public Compiler ( int CompilerOption ) { } private final boolean enablePackratParsing ( ) { } private final boolean enableASTConstruction ( ) { } MemoPoint issueMemoPoint ( String label , Expression e ) { } private UMap < String > visitedMap = null ; private boolean isContextSensitive ( Expression e ) { } public final int getInstructionSize ( ) { } public final int getMemoPointSize ( ) { } public final UList < MemoPoint > getMemoPointList ( ) { } public final Instruction encode ( UList < Rule > ruleList ) { } void encode ( Instruction inst ) { } public void dump ( UList < Rule > ruleList ) { } public final Instruction encodeMatchAny ( AnyChar p , Instruction next ) { } public final Instruction encodeByteChar ( ByteChar p , Instruction next ) { } public final Instruction encodeByteMap ( ByteMap p , Instruction next ) { } public Instruction encodeFail ( Expression p ) { } public final Instruction encodeRepetition ( Repetition p , Instruction next ) { } public final Instruction encodeRepetition1 ( Repetition1 p , Instruction next ) { } public final Instruction encodeOption ( Option p , Instruction next ) { } public final Instruction encodeAnd ( And p , Instruction next ) { } public final Instruction encodeNot ( Not p , Instruction next ) { } public final Instruction encodeSequence ( Expression p , Instruction next ) { } public final Instruction encodeChoice ( Choice p , Instruction next ) { } public final Instruction encodeUnoptimizedChoice ( Choice p , Instruction next ) { } public final Instruction encodeNonTerminal ( NonTerminal p , Instruction next ) { } private Instruction newLookup ( Expression e , MemoPoint m , Instruction next , Instruction skip , Instruction failjump ) { } private Instruction newMemoize ( Expression e , MemoPoint m , Instruction next ) { } private Instruction newMemoizeFail ( Expression e , MemoPoint m ) { } public final Instruction encodeLink ( Link p , Instruction next ) { } private Instruction newLookupNode ( Link e , MemoPoint m , Instruction next , Instruction skip , Instruction failjump ) { } private Instruction newMemoizeNode ( Link e , MemoPoint m , Instruction next ) { } public final Instruction encodeNew ( NewClosure p , Instruction next ) { } public final Instruction encodeLeftNew ( LeftNew p , Instruction next ) { } public final Instruction encodeNew ( New p , Instruction next ) { } public final Instruction encodeCapture ( Capture p , Instruction next ) { } public final Instruction encodeTagging ( Tagging p , Instruction next ) { } public final Instruction encodeReplace ( Replace p , Instruction next ) { } public final Instruction encodeBlock ( Block p , Instruction next ) { Instruction failed = new ITablePop ( p , new IFail ( p ) ) ; <START_BUG> Instruction inner = p . get ( 0 ) . encode ( this , new ITablePop ( p , next ) ) ; <END_BUG> return new ITablePush ( p , new IFailPush ( p , failed , inner ) ) ; } public final Instruction encodeDefSymbol ( DefSymbol p , Instruction next ) { } public final Instruction encodeIsSymbol ( IsSymbol p , Instruction next ) { } public final Instruction encodeDefIndent ( DefIndent p , Instruction next ) { } public final Instruction encodeIsIndent ( IsIndent p , Instruction next ) { } }

Fix:
Instruction inner = p . get ( 0 ) . encode ( this , new IFailPop ( p , new ITablePop ( p , next ) ) ) ;